The objective is to design, fabricate and test a prosthetic trileaflet aortic heart valve. Seven simultaneous studies were started concerning 1) the uniaxial and biaxial properties of fresh and frozen human aortic leaflets, 2) hydrodynamic analyses concerning the dynamics of flow as related to valve position and size, shape and proportionalities as a function of pressure, 3) unique stress distribution analyses of the leaflets, annulus and aortic wall employing close-range stereophotogrammetry and computer analyses with a finite element method, 4) material development of ultra-pure polymer, fiber syntheses and methods of fabrication including microfiber surfaces, 5) characterization of the normal valvular surfaces and discrimination of fiber orientation as a function of pressure states using scanning electron microscopy, 6) development of an automated system for measuring and controlling flow and pressure and time lapse photography in a high speed fatigue testing device and 7) biologic prosthetic material surface testing used in spinning disc apparatus for red-cell adhesion, analysis for the influence of porosity and fiber diameter on cellular infiltration and vascular replacements. Final biologic evaluation of the prosthetic trileaflet aortic valve will be in primates where there to five year survival of ten animals will be sought.